Typical hair conditioning products have a particular thick rheology that is desirable for such products. These products are based on the combination of a surfactant, which is generally a quaternary ammonium compound, and a fatty alcohol. This combination results in a gel-network structure which provides the composition with a thick rheology. However, while such compositions deliver conditioning benefits to the hair, such compositions also deposit in hair making hair look and feel dirty.
Alternative thickening systems have been used in hair care compositions, but none have been found to date which provide this same desirable rheology. Though hair care products thickened with polymer thickeners can be made to have a thick rheology, these products generally are characterized by an undesirable "slimy"feel and do not hold their poured shape.
Nonionic water-soluble cellulose ethers are employed in a variety of applications, including hair care compositions. Widely used, commercially-available nonionic cellulose ethers include methyl cellulose, hydroxy propyl methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose and ethyl hydroxyethyl cellulose.
Better thickening efficiency is realized with higher molecular weight cellulose ethers. However, production of such materials is difficult and expensive. Though crosslinking of these polymers is an alternative means to achieve high viscosity solutions, good crosslinking techniques are not known. Of course, high concentrations of polymers will also provide high viscosity but such an approach is inefficient and impractical, particularly due to the high expense involved. Furthermore, use of highly crosslinked polymers or high levels of polymeric thickeners may result in a vehicle system that is too elastic for the present uses.
Alternative water-soluble polymeric thickeners sometimes used to thicken hair care compositions are natural polysaccharides such as guar gum, xanthan gum and locust bean gum.
A number of references teach the use of nonionic cellulose ethers and water-soluble gums for thickening hair care compositions. See for example, U.S. Pat. No. 4,577,928, Glover, issued Dec. 10, 1985, teaching a hair conditioner comprising a suspension system which consists of one of glucan gum, guar gum, and hydroxyethylcellulose; and U.S. Pat. No. 4,581,230, Grollier et al;, issued Apr. 8, 1986, which teaches cosmetic compositions for treating hair which comprise as thickening agents hydroxyethylcellulose, or water-soluble vegetable thickening agents, such as guar gum. Japanese Patent Publication 61-053211, published Mar. 7, 1986, discloses a hair colorant containing an aromatic alcohol, xanthan gum, and hydroxyethylcellulose.
Certain cellulose ethers have been disclosed in U.S. Pat. No. 4,228,277, Landoll, issued Oct. 14, 1980, which are relatively low molecular weight but which are capable of producing highly viscous aqueous solutions in practical concentrations. These materials are nonionic cellulose ethers having a sufficient degree of nonionic substitution selected from the group consisting of methyl, hydroxyethyl, and hydroxypropyl to cause them to be water-soluble and which are further substituted with a hydrocarbon radical having from about 10 to 24 carbon atoms in an amount between about 0.2 weight percent and the amount which renders said cellulose ether less than 1%, by weight, soluble in water. The cellulose ether to be modified is preferably one of low to medium molecular weight; i.e., less than about 800,000 and preferably between about 20,000 and 700,000 (about 75 to 2500 D.P.).
These modified cellulose ethers have been disclosed for use in a variety of composition types. Landoll ('277) teaches the use of these materials in shampoo formulations. Hercules trade literature teaches the use of these materials in shampoos, liquid soaps, and lotions. U.S. Pat. No. 4,683,004, Goddard, issued July 28, 1987, discloses the use of these materials in mousse compositions for the hair. U.S. Pat. No. 4,485,089, Leipold, issued Nov. 27, 1984, teaches dentifrice compositions containing these materials.
These materials have now been found to provide a rheology very much like the desirable gel-network structure of typical hair conditioners (without the slimy feel associated with most polymeric thickeners), when they are combined with surfactants at certain critical levels.
Hence, it is an object of the present invention to provide a vehicle system for hair care and other cosmetic compositions which provides a gel-network-like structure to the composition but which is not based on a typical quaternary ammonium compound/fatty alcohol gel-network thickening system.
It is also an object of the present invention to provide a vehicle system for hair care and other cosmetic compositions which allows for dispersion of a wide variety of active hair or skin care components therein.
It is also an object of the present invention to provide a vehicle system for hair care and other cosmetic compositions which will maximize deposition of the active hair or skin care component contained therein onto the hair or skin while minimizing deposition of the vehicle system components.
These other objects will become readily apparent from the detailed description which follows.